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A351477
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a(n) is the common denominator of FA, FB and FC, where F is the Fermat point of the integer-sided triangle ABC with A < B < C < 2*Pi/3 such that FA + FB + FC = A336329(n).
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8
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7, 7, 37, 283, 91, 331, 331, 13, 43, 97, 43, 13, 691, 37, 91, 193, 349, 13, 283, 211, 97, 91, 379, 409, 7, 97, 691, 613, 13, 19, 13, 91, 2593, 19, 349, 43, 1, 337, 97, 169, 37, 19, 31, 409, 3217, 67, 571, 169, 241, 43, 67, 157, 4171, 3601, 889, 1591, 811, 1, 139
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OFFSET
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1,1
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COMMENTS
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Inspired by Project Euler, Problem 143 (see link).
For the corresponding primitive triples, miscellaneous properties and references, see A336328.
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LINKS
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FORMULA
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a(n) is the common denominator of fractions FA, FB, FC when FA = sqrt(((2*b*c)^2 - (b^2+c^2-d^2)^2)/3) / d, FB = sqrt(((2*a*c)^2 - (a^2+c^2-d^2)^2)/3) / d, FC = sqrt(((2*a*b)^2 - (a^2+b^2-d^2)^2)/3) / d, with a = (A336328(n,1), b = (A336328(n,2), c = (A336328(n,3)) and d = A336329(n) (formulas FA, FB, FC from Jinyuan Wang, Feb 17 2022).
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EXAMPLE
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For 1st triple (57, 65, 73) in A336328, we get A336329(1) = FA + FB + FC = 325/7 + 264/7 + 195/7 = 112, hence a(1) = 7.
For 3rd triple (43, 147, 152) in A336328, we get A336329(3) = FA + FB + FC = 5016/37 + 1064/37 + 765/37 = 185, hence a(3) = 37.
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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